The present invention relates to divisible solid dosage forms, in particular solid pharmaceutical dosage forms, and to a process for their production.
It is often desirable for solid pharmaceutical dosage forms, for example tablets, to be divisible in order to be able to alter the dosage without the need to produce individual tablets for each particular dosage. Division of a tablet into accurately predetermined parts makes it possible to administer a fraction or any multiple of the fraction of the active ingredient present in the tablet.
To facilitate division, tablets normally have scores. The tablet is broken apart by exerting pressure on the tablet, with the tablet being held between two fingers or with both hands. Divisible tablets are described, for example, in CH 683 066 or U.S. Pat. No. 3,927,194.
DE-B 30 30 622 describes a divisible tablet with controlled and delayed release of active ingredient. The ratio of length to width to height in this case is intended to be about 2.5-5:about 0.9-2:1. One or more relatively deep score(s) running perpendicular to the length and to the height are present. The bottom and top surfaces are, independently of one another, flat or curved convexly around the long axis or parallels thereto.
DE-B 44 46 470 describes a process for producing divisible tablets by shaping an active ingredient-containing melt in a calender with two counter-rotating molding rolls which have depressions for receiving and molding the melt to tablets, where the depressions are divided by at least one bar which extends essentially as far as the surface of the molding roll and forms a score.
One problem with the known divisible solid dosage forms is that expenditure of a relatively large force is necessary to divide the dosage forms. This problem is particularly pronounced with dosage forms produced by melt extrusion because they usually consist of a very hard and brittle material. Attempts have been made to bypass this problem by providing the solid dosage forms with very deep notches with large notch angles. However, with these approaches to a solution there is the risk that the solid dosage form will break during after-treatment steps, e.g. during deflashing or film-coating, due to the stress on the material, which leads to a large proportion of rejects.
A further serious problem with known divisible solid dosage forms is the inadequate uniformity of mass of the manually divided halves of the dosage forms. Corresponding investigations have revealed standard deviations of between 3 and 13% for the tablet halves (see H. G. Kristensen et al., Pharmeuropa, Volume 7, No. 2, June 1995, pp. 298 et seq.). Standard deviations as high as this lead to inaccurate dosages, which is particularly undesirable with active ingredients of high activity. The inadequate uniformity of mass of the manually divided tablet halves derives, on the one hand, from the fractures area not being exactly at the intended place and, on the other hand, from the tendency of the tablet material to escape at outer edges of the tablet mold, which leads to losses of active ingredient.
It is an object of the present invention to provide solid dosage forms which display easy divisibility and, at the same time, a sufficient resistance to stress for further processing steps. It was additionally intended that the solid dosage forms be of a nature such that the fragments resulting from manual division of the solid dosage forms display a maximum uniformity of mass.
We have found that this object is achieved by the solid dosage forms having a particular geometry. The present invention therefore relates to a solid, elongate dosage form (10) with a long axis (11) and with a length (L) which is defined by projection of the ends (12, 13) of the dosage form onto the long axis, where a cross-sectional area (14, 15, 16) oriented perpendicular to the long axis (11) has an area which is variable along the long axis (11) and increases from a cross-sectional area (15) which is located between the ends (12, 13) and has a minimal area essentially continuously toward the two ends (12, 13) up to in each case a cross-sectional area (14 and 16 respectively) with a maximal area, wherein the distance of the maximal cross-sectional area (14) which is located near one end (12) from the maximal cross-sectional area (16) which is located near the other end (13) is, projected on the long axis (11), more than half the length (L) of the dosage form (10).